pretty good, is this something you're building or what? the 7790 isn't a top of the line card but it is one of the best value and should be fine. the 8120 isnt the greatest cpu thats why i ask if you're building it or what because a fx 6300 would probably be better, or of course the 8350/8320 are better. also if this is pre built what are you/did you pay, dont want you getting ripped off or anything.
okay it looks pretty good but i would swap the 8120 for the 6300 (its cheaper and in gaming where games generally use a max of 6 cores it will be better. http://www.anandtech.com/bench/product/434?vs=699
look at that comparison, go down to the gaming spot, or anywhere i guess, the 6300 generally wins and with piledriver having a pretty good ipc in comparison to bulldozer the 6300 will work better. plus that compares the 8150 which is clocked .5ghz higher than the 8120
the 7790 should be good enough i was planing on doing a similar build within a few months actually, i plan on using the 6300 and a 7790 as both have great price/performance
i didnt look into the ram but try and get 1866mhz ram, it helps and isnt that much more money. you can probably get a weaker psu (maybe use savings for a little better gpu like the 7850) 750w is a lot, you should be fine with a 500 or 600w
those are basically my suggestions i dont know about maxing bf3 or cyrsis 3 (might be able to without filter and AA on bf3, i have no clue about cyrsis)